Surface Segregation and Wetting from Polymer Mixtures

1994 ◽  
pp. 313-322 ◽  
Author(s):  
Ullrich Steiner ◽  
Erika Eiser ◽  
Andrzej Budkowski ◽  
Lewis Fetters ◽  
Jacob Klein
Keyword(s):  
Surface Segregation ◽  
Polymer Mixtures

scholarly journals Gelation Impairs Phase Separation and Small Molecule Migration in Polymer Mixtures

Polymers ◽  
2020 ◽  
Vol 12 (7) ◽  
pp. 1576
Author(s):  
Biswaroop Mukherjee ◽  
Buddhapriya Chakrabarti
Keyword(s):  
Phase Separation ◽  
Rational Design ◽  
Surface Segregation ◽  
Multiscale Methods ◽  
Coarse Grained ◽  
Polymer Gel ◽  
Polymer Mixtures ◽  
Separation Processes ◽  
Surface Migration ◽  
Wide Range

Surface segregation of the low molecular weight component of a polymeric mixture is a ubiquitous phenomenon that leads to degradation of industrial formulations. We report a simultaneous phase separation and surface migration phenomena in oligomer–polymer ( O P ) and oligomer–gel ( O G ) systems following a temperature quench that induces demixing of components. We compute equilibrium and time varying migrant (oligomer) density profiles and wetting layer thickness in these systems using coarse grained molecular dynamics (CGMD) and mesoscale hydrodynamics (MH) simulations. Such multiscale methods quantitatively describe the phenomena over a wide range of length and time scales. We show that surface migration in gel–oligomer systems is significantly reduced on account of network elasticity. Furthermore, the phase separation processes are significantly slowed in gels leading to the modification of the well known Lifshitz–Slyozov–Wagner (LSW) law ℓ ( τ ) ∼ τ 1 / 3 . Our work allows for rational design of polymer/gel–oligomer mixtures with predictable surface segregation characteristics that can be compared against experiments.

surface Enrichment in Polymer Blends: Simple Theory and an Experimental Test

1989 ◽  
Vol 154 ◽  
Author(s):  
R.A.L. Jones ◽  
E.J. Kramer ◽  
M.H. Rafailovich ◽  
J. Sokolov ◽  
S.A. Schwarz
Keyword(s):  
Friction And Wear ◽  
Surface Segregation ◽  
Phase Region ◽  
Polymer Mixture ◽  
Recent Theory ◽  
Polymer Mixtures ◽  
Surgical Implants ◽  
Polymeric Solid ◽  
Interface Segregation ◽  
Strength Of Adhesive Joints

AbstractIf a polymer mixture which is in the bulk one-phase region is next to an interface - this may be with another polymer, with a non-polymeric solid, or with the air - the composition of the mixture at the interface will be different from the bulk [1–4]. There are two questions we would like to understand: what determines the composition of the mixture at the interface, and how does that composition increment decay back to the bulk value. This surface or interface segregation has important practical consequences; in the surface case such segregation will profoundly affect wettability, with consequences for the strength of adhesive joints and the biocompatibility of polymeric surgical implants, as well as influencing friction and wear; at interfaces with non-polymers segregation is important for the adhesion of mixed polymer phases to non-polymer phases such as reinforcing fibres or fillers. In this paper we describe some experiments on surface segregation in a very well characterised model system and we describe a recent theory that can be quantitatively tested by our data. We will consider the consequences of this new understanding of surface segregation in polymer mixtures, and we will argue that many of these conclusions may be carried over to the more general case of interface segregation, which opens up a number of interesting technological possibilities.

Surface Enrichment in Polymer Blends: Simple Theory and an Experimental Test

1989 ◽  
Vol 153 ◽  
Author(s):  
R.A.L. Jones ◽  
E.J. Kramer ◽  
M.H. Rafailovich ◽  
J. Sokolov ◽  
S.A. Schwarz
Keyword(s):  
Friction And Wear ◽  
Surface Segregation ◽  
Phase Region ◽  
Polymer Mixture ◽  
Recent Theory ◽  
Polymer Mixtures ◽  
Surgical Implants ◽  
Polymeric Solid ◽  
Interface Segregation ◽  
Strength Of Adhesive Joints

If a polymer mixture which is in the bulk one-phase region is next to an interface - this may be with another polymer, with a non-polymeric solid, or with the air - the composition of the mixture at the interface will be different from the bulk [1-4]. There are two questions we would like to understand: what determines the composition of the mixture at the interface, and how does that composition increment decay back to the bulk value. This surface or interface segregation has important practical consequences; in the surface case such segregation will profoundly affect wettability, with consequences for the strength of adhesive joints and the biocompatibility of polymeric surgical implants, as well as influencing friction and wear; at interfaces with non-polymers segregation is important for the adhesion of mixed polymer phases to non-polymer phases such as reinforcing fibres or fillers. In this paper we describe some experiments on surface segregation in a very well characterised model system and we describe a recent theory that can be quantitatively tested by our data. We will consider the consequences of this new understanding of surface segregation in polymer mixtures, and we will argue that many of these conclusions may be carried over to the more general case of interface segregation, which opens up a number of interesting technological possibilities.

scholarly journals Elasticity Dominated Surface Segregation of Small Molecules in Polymer Mixtures

2016 ◽  
Vol 116 (20) ◽  
Author(s):  
Jarosław Krawczyk ◽  
Salvatore Croce ◽  
T. C. B. McLeish ◽  
Buddhapriya Chakrabarti
Keyword(s):  
Small Molecules ◽  
Surface Segregation ◽  
Polymer Mixtures

Surface segregation in binary polymer mixtures: a lattice model

1991 ◽  
Vol 24 (17) ◽  
pp. 4909-4917 ◽  
Author(s):  
Arvind Hariharan ◽  
Sanat K. Kumar ◽  
Thomas P. Russell
Keyword(s):  
Lattice Model ◽  
Surface Segregation ◽  
Polymer Mixtures ◽  
Binary Polymer

The effect of finite film thickness on the surface segregation in symmetric binary polymer mixtures

1993 ◽  
Vol 99 (1) ◽  
pp. 656-663 ◽  
Author(s):  
Arvind Hariharan ◽  
Sanat K. Kumar ◽  
Miriam H. Rafailovich ◽  
Jonathan Sokolov ◽  
X. Zheng ◽  
...  
Keyword(s):  
Film Thickness ◽  
Surface Segregation ◽  
Polymer Mixtures ◽  
Binary Polymer

Near-Surface Aggregation of Sn In Heavily Sn-Doped GaAs Films Grown By Molecular Beam Epitaxy

1985 ◽  
Vol 43 ◽  
pp. 368-369
Author(s):  
S. H. Chen
Keyword(s):  
Molecular Beam Epitaxy ◽  
Cross Section ◽  
Electron Spectroscopy ◽  
Molecular Beam ◽  
Surface Segregation ◽  
Secondary Ion Mass Spectrometry ◽  
Specimen Preparation ◽  
Near Surface ◽  
Gaas Films ◽  
Secondary Ion

Sn has been used extensively as an n-type dopant in GaAs grown by molecular-beam epitaxy (MBE). The surface accumulation of Sn during the growth of Sn-doped GaAs has been observed by several investigators. It is still not clear whether the accumulation of Sn is a kinetically hindered process, as proposed first by Wood and Joyce, or surface segregation due to thermodynamic factors. The proposed donor-incorporation mechanisms were based on experimental results from such techniques as secondary ion mass spectrometry, Auger electron spectroscopy, and C-V measurements. In the present study, electron microscopy was used in combination with cross-section specimen preparation. The information on the morphology and microstructure of the surface accumulation can be obtained in a fine scale and may confirm several suggestions from indirect experimental evidence in the previous studies.

A New Numerical Model for Electron-Probe Analysis at High Depth Resolution

1996 ◽  
Vol 54 ◽  
pp. 490-491
Author(s):  
P.-F. Staub ◽  
C. Bonnelle ◽  
F. Vergand ◽  
P. Jonnard
Keyword(s):  
Electron Probe ◽  
Surface Segregation ◽  
Depth Distribution ◽  
Computing Time ◽  
Depth Resolution ◽  
Physical Parameters ◽  
Electron Probe Analysis ◽  
Interface Phases ◽  
Excitation Conditions ◽  
High Depth

Characterizing dimensionally and chemically nanometric structures such as surface segregation or interface phases can be performed efficiently using electron probe (EP) techniques at very low excitation conditions, i.e. using small incident energies (0.5<E0<5 keV) and low incident overvoltages (1<U0<1.7). In such extreme conditions, classical analytical EP models are generally pushed to their validity limits in terms of accuracy and physical consistency, and Monte-Carlo simulations are not convenient solutions as routine tools, because of their cost in computing time. In this context, we have developed an intermediate procedure, called IntriX, in which the ionization depth distributions Φ(ρz) are numerically reconstructed by integration of basic macroscopic physical parameters describing the electron beam/matter interaction, all of them being available under pre-established analytical forms. IntriX’s procedure consists in dividing the ionization depth distribution into three separate contributions:

Surface segregation in model symmetric polyolefin diblock copolymer melts

1994 ◽  
Vol 4 (12) ◽  
pp. 2231-2248 ◽  
Author(s):  
Mohan Sikka ◽  
Navjot Singh ◽  
Frank S. Bates ◽  
Alamgir Karim ◽  
Sushil Satija ◽  
...  
Keyword(s):  
Diblock Copolymer ◽  
Surface Segregation ◽  
Copolymer Melts
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